CASE-BASED SMALL GROUP DISCUSSION

Transcription

1 MHD I Session 2 STUDENT Copy Page 1 CASE-BASED SMALL GROUP DISCUSSION MHD I SESSION 2 Bacteria Friday, September 9, 2016 STUDENT COPY

2 MHD I Session 2 STUDENT Copy Page 2 Helpful Session Resources Murray s Medical Microbiology Table 15-2, p p p p Robbins Basic Pathology p Case 1: I probably have another UTI x 2 days History of Present Illness: A 37-year-old woman presents to the emergency department with fever for 2 days. She developed paraplegia from a gunshot wound 8 years ago and has required an indwelling bladder catheter since. Her appetite has been decreased for the past three days. She developed chills just as she arrived to the emergency department. She has had multiple urinary tract infections over the past 8 years with multiple hospitalizations and states this is exactly how I feel when I get a bladder infection Additional chronic medical problems: none known Medications: Baclofen 10mg tid Multivitamin daily Ibuprofen 400mg every 6 hours as needed for pain (pt rarely takes) Tap water rectal enemas 3x/week Social history: The patient lives with her sister. She smokes ½ pack cigarettes per day for 10 years. She rarely drinks alcohol. Review of Systems: Pulmonary no cough, no SOB GI no change in caliber or quantity of stool GU no vaginal discharge, LMP 1 week ago ENT no sore throat or runny nose Skin no decubitus ulcers Musculoskeletal she is able to independently transfer to and from her wheelchair Physical Exam: The patient appears fatigued Temperature F, Blood pressure 96/54, Pulse 110, Respiratory rate 16 Head and neck no abnormal findings Lungs Clear to auscultation, normal percussion

3 MHD I Session 2 STUDENT Copy Page 3 Heart S1S2 tachycardic, regular, no S3 or S4, no murmur Abdomen - +BS, soft, nondistended, no tenderness elicited, no masses, no hepatosplenomegaly Extremities - no peripheral edema, 2+ radial and DP pulses. Skin no decubitus ulcers, no rash Urinalysis Color YELLOW [YELLOW] Clarity CLOUDY [CLEAR] PH 8.7 [ ] Specific Gravity [ ] Protein NEG [Negative] Blood POS [Negative] Glucose NEG [Negative] Ketones POS [Negative] Bilirubin NEG [Negative] Urobilinogen 0.4 [ ] eu/dl NITRITE POS [Negative] LEUKOCYTES POS [Negative] RBC 10 [0-2] /hpf WBC >180 [0-5] /hpf Bacteria MANY The patient is admitted to the hospital with a diagnosis of urinary tract infection. She is begun on intravenous fluids and antibiotics. Learning Objectives 1. List bacteria which commonly cause urinary tract infections On hospital day 2 the following results are reported: Urine Culture >100, 000 colonies, Gram negative rod, non-lactose fermenter Blood Culture Gram negative rod, non-lactose fermenter Blood Culture Gram negative rod, non-lactose fermenter

4 MHD I Session 2 STUDENT Copy Page 4 The bacteria have a swarming appearance on the agar plate (see Small Group Image Bacteriology Set 5) 2. List the lactose fermenting and non-lactose fermenting Enterobacteriaceae. Why is knowing this clinically relevant? 3. Based on the given information, what is the most likely etiologic agent of this patient s urinary tract infection? (complete the road map as a review) The medical team orders a renal ultrasound which shows the presence of a staghorn calculus in the right kidney 4. What is the link, if any, between this organism and the renal ultrasound finding?

5 MHD I Session 2 STUDENT Copy Page 5 CASE 2: Cc: feeling terrible and getting worse x 2 weeks A 25 year-old man is brought to the emergency department by his wife with a 2 week history of easy fatigability, dyspnea on exertion, easy bruising and bleeding gums. Over the last 24 hours, the patient developed a fever of 104 F, shaking chills, confusion and severe weakness. He could not get out of bed. The patient denies cough, sputum production, nausea, vomiting, stiff neck, dysuria, frequency of urination. Patient has no significant past medical history and takes no medications. He has no drug allergies. He smoked 1 pack of cigarettes a day for two years then stopped. He does not drink alcohol. His parents, two sisters and one brother are alive and healthy. PE: Patient appears pale, sleepy but arousable, oriented to person but not to time or place VS: HR 120 weak, BP 70 palpable, R22, T 39.7 orally. Mouth: bleeding gums Lymph Nodes: enlarged non-tender cervical and axillary nodes (up to 1.5cm) Neck: supple, full range of motion Lungs: Clear to auscultation and percussion bilaterally CV - S 1. and S 2 NL, no S3/ S4, SEM 3/6 at LLSB Abd: soft non-tender, liver span 14 cm and tender, spleen tip felt Ext: cool, clammy, purplish mottling Skin: Scattered petechiae, black raised 1 cm lesion on left leg, no fluctuance or drainage of the lesion Rectal: No external lesions, digital exam not done Neuro: cranial nerves 2-12 intact, reflexes 2+ symmetrical, plantar reflexes downgoing Heme Final X42590 CBC w/ DIFF WBC 1.0 L [ ] k/ul RBC 2.04 L [ ] m/ul Hgb 7.4 L [ ] gm/dl Hct 22.2 L [ ] % MCV 85 [85-95] fl MCH 28.3 [ ] pg MCHC 33.3 [ ] gm/dl RDW 16.6 H [ ] % Plt Count 7 LL [ ] k/ul Diff Type Manual Blasts % 20 Blasts 0.2 Gran 20 L [45-70] % Gran # 0.2 L [ ] k/mm3 Lymph 45 [20-45] % Lymph #.45 [ ] k/mm3 Mono 15 [0-10] % Mono # 0.15 [ ] k/mm3 Eo 0.0 [0-7] %

6 MHD I Session 2 STUDENT Copy Page 6 Eo # 0 [ ] k/mm3 Baso 0 [0-2] % Baso # 0.0 [ ] k/mm3 *Slide review by pathologist performed Urine Final - X1668 Urinalysis Color YELLOW [YELLOW] Clarity CLEAR [CLEAR] PH 5.7 [ ] Specific Gravity [ ] Protein 1+ [Negative] Blood Trace [Negative] Glucose NEG [Negative] Ketones Neg [Negative] Bilirubin NEG [Negative] Urobilinogen 0.4 [ ] eu/dl NITRATE NEG [Negative] LEUKOCYTES NEG [Negative] RBC 2-5 [0-2] /hpf WBC 0-2 [0-5] /hp Nonrenal Epith Cells 0 [0-5] /hpf Mucous NEG [Negative] Micro - Blood Culture (Accessioned) - X63610 Micro - Blood Culture (Accessioned) - X62611 Micro Urine Culture (Accessioned) - X62617 EXAM: DXCPAL - CHEST 2 VIEWS, FRONTAL (AP OR PA) AND LATERAL EXAM: PA AND LATERAL CHEST COMPARISON: NONE HISTORY: FEVER FINDINGS: THE CARDIAC SILHOUETTE AND PULMONARY VASCULATURE ARE NORMAL. THERE IS NO FOCAL PARENCHYMAL ABNORMALITY, PLEURAL EFFUSION, PULMONARY EDEMA OR PNEUMOTHORAX. *THIS EXAMINATION AND REPORT HAVE BEEN REVIEWED BY THE* *ATTENDING RADIOLOGIST WHOSE NAME APPEARS ON THIS REPORT* Despite aggressive intravenous fluid administration, it was initially difficult to maintain his systolic blood pressure >90 mm Hg. Broad spectrum intravenous antibiotics are begun. The patient was given blood products (packed red blood cells and platelets). A bone marrow biopsy was done and the diagnosis of acute lymphoblastic leukemia was made.

7 MHD I Session 2 STUDENT Copy Page 7 The next day blood cultures were growing a Gram negative non-lactose fermenting rod. Learning Objectives 1. Develop a problem list. Reminder of what problems are: Diagnoses ie CAD, type 2 DM, asthma Physiologic findings ie CHF, acute renal failure Symptoms or physical findings ie fever, abdominal pain, epigastric tenderness to palpation Abnormal lab/test results Family history ie family history of breast cancer Social ie tobacco use, alcohol abuse Prior surgeries Allergies 2. The intensive care unit team contacts the Microbiology lab to learn more about the bacteria growing in the blood cultures to assure their empiric antibiotic therapy is appropriate. It is an aerobic, Gram negative, nonlactose fermenting, oxidase positive rod which produces pyocyanin pigment. What is the likely pathogen? 3. Why is this patient hypotensive? Summarize the pathogenesis.

8 MHD I Session 2 STUDENT Copy Page 8 4. In general terms, discuss the approach to antibiotic therapy for this pathogen. 5. What are the risk factors for infection with this organism in this patient? What are other risk factors for infection with this organism? 6. What is the black raised 1 cm lesion on the left leg of this patient? Describe the pathogenesis. 7. Review the Case Images Bacteriology Set Which of the following would be appropriate antibiotic options to treat this patient s infection? Base your answers on the specific bacteria isolated from the blood cultures. Discuss your rationale for each of the options. a) Carboxypenicillin - ticarcillin b)third generation cephalosporin ceftazidime

9 MHD I Session 2 STUDENT Copy Page 9 c)penicillin-resistant penicillin - nafcillin d)third generation cephalosporin ceftriaxone e)uredopenicillin - piperacillin f) Fluoroquinolone levofloxacin g)first generation cephalosporin cephalexin h)aminoglycoside - tobramycin i)fourth generation cephalosporin cefepime j) Fluoroquinolone ciprofloxacin k)combination penicillin and beta lactamase inhibitor ticarcillin-clavulanate l)combination penicillin and beta lactamase inhibitor ampicillin-sulbactam m)fluoroquinolone moxifloxacin n)vancomycin Case 3 Cc: Headache for 3 days The patient is a 30-year-old woman who is a recipient of a renal transplant 3 years ago. She presents to the emergency department with complaints of headache and an inability to concentrate for the past several days. She has felt feverish but did not take her temperature. She has had mild intermittent nausea but no vomiting. She is more sensitive to bright lights than usual. Her car has been undergoing repairs for the past 2 weeks so she had not left home much. She remembers her last trip out was to a Mexican restaurant where she had a burrito and soft cheese. No one in her family is sick. She has not traveled outside of Chicago recently. She has no pets. Her medications include cyclosporine, azathioprine, and prednisone.

10 MHD I Session 2 STUDENT Copy Page 10 On examination she had a temperature of 39 0 C, blood pressure 100/60, pulse 96, and respirations 18. She appeared anxious and fidgety. Her lung and heart exams were normal. Her abdominal exam was unremarkable aside from her palpable, nontender transplanted kidney. On full neurologic examination there were no motor or sensory abnormalities. Reflexes were normal. There were no skin abnormalities. Fundoscopic examination was normal with no evidence of papilledema. A lumbar puncture is peformed. Chem Final Glu & Protein, CSF Glucose, CSF 30 [45-75] mg/dl Protein 90 [15-45] mg/dl Spinal Fluid Cnt Volume 2.0 ml RBC 0 [0] /ul WBC 112 [0-8] /ul Seg 0% Lymph 100% BASIC METABOLIC PNL Sodium 139 [ ] mm/l Potassium 4.0 [ ] mm/l Chloride 105 [98-108] mm/l CO2 27 [20-32] mm/l Glucose 109 [70-100] mg/dl Bun 12 [7-22] mg/dl Creatinine 1.4 [ ] mg/dl Learning Objectives: 1. Interpret the cerebrospinal fluid analysis. Develop a differential diagnosis for the abnormality.

11 MHD I Session 2 STUDENT Copy Page 11 Interpretation of CSF Analyses: Cerebrospinal Fluid Abnormalities in Various Central Nervous System Conditions Complete the following table - it will be a helpful resource for MHD, USMLE and your clerkships (it is acceptable to use up/down arrows to indicate elevated or decreased values for CSF glucose, protein, cell count and opening pressure) Condition CSF Appearance CSF Glucose (mg/dl) CSF Protein (mg/dl) CSF Cell Count (cells/mm 3 ) and Cell Type Opening Pressure (mm Hg) Normal Acute bacterial meningitis Aseptic (viral) meningitis Hemorrhage Tuberculous meningitis Fungal meningitis CSF cultures, as well as 2 sets of blood cultures, grew colonies of non-spore forming Gram positive rods with small zones of beta-hemolysis. The colonies are catalase positive. Suspensions of the colonies demonstrate tumbling/umbrella motility at room temperature. 2. What organism do the cultures represent? (complete the road map as a review) What is your diagnosis? Do the CSF findings support your diagnosis?

12 MHD I Session 2 STUDENT Copy Page Based on the history provided, how might the patient have acquired this infection? 4. What factors predisposed this patient to infection? 5. The recommended treatment for serious infections caused by this organism is ampicillin with gentamycin. This combination of drugs results in synergy describe how/why. 6. To what group of antibiotics is this bacteria naturally resistant?

13 MHD I Session 2 STUDENT Copy Page Review the Case Images: Bacteriology Set 13 Asking a Clinical Question Assignment REMINDER: One student has been assigned (please see the schedule) to develop a clinical question which has arisen during today s case discussions. This should be a specific answerable question regarding one of your small group case patients. Focus on developing a foreground question about the type of decision you will need to make as a clinician. The question could focus on an aspect such as diagnostic testing, drug therapy, specific intervention, risk factor, or prognosis related to the patient s disease process. Please ask your small group colleagues and facilitator to help develop this question with you.